Form I-485, Adjustment of Status
The same few things, over and over — and every one of them is a completeness problem the software checks for before your packet is marked ready.
Watch for
Rushing the yes/no eligibility questions — a wrong checkbox here is serious
Filing when the category is not actually open for adjustment
A medical exam that is missing, unsealed, or out of date
Leaving the U.S. while it is pending without advance parole — that can abandon the application
Form I-485
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